Plants of Casa Grande Ruins National Monument Editor Steve Buckley Plants of Casa Grande Ruins National Monmument Editor: Steve Buckley The ethnobotanical information in this book is included for educational purposes only. No plant or plant extract should be consumed unless you are certain of its identity and toxicity and of your personal potential for allergic reactions. Self-medication with herbal medicines is often unwise and wild foods should always be used with caution. Although every effort has been made to ensure accuracy and reliability, neither the author, the Sonoran Desert Network Inventory and Monitoring Program, the National Park Service, nor the University of Arizona are responsible for the actions of the reader or liable for any effects caused by these actions. This field guide is for educational use only. It has not been produced for commercial uses. Please consult the works cited page at the end of the book for those works consulted, for further reading, more complete botanical descriptions, further citations and credits. Cover Photo Credits: Center: 2008 NPS; Insets: Right, © 2008-2009 Patrick Alexander; Bottom, 2009-2010 NPS. Plants of Casa Grande Ruins National Monument Introduction to Casa Grande Ruins NM 8 Vegetation Mapping and Community Types 11 How to Use this Guide 23 Ferns 35 Graminoids 37 Flowering Trees & Shrubs 49 Cacti 69 Forbs 73 Glossary 131 Works Cited 153 Index 161 Casa Grande Ruins NM Checklist 165 The Flora Project This field guide is part of a larger body of work known as the Flora of the Sonoran Desert Network. The Flora Project emerged from the network’s vegetation mapping program, begun in 2009. Since then, we have compiled comprehensive floristic entries on upwards of 2,000 individual species, the ultimate goal being to build a comprehensive floristic database covering the more than 2,400 species, subspecies, and varieties of plants found in the national parks of the Sonoran Desert Network (SODN). These entries will ultimately be available as an online database and also translate directly into the work presented in this guide. The goal of the project is to produce (1) a comprehensive field guide for each SODN park unit, (2) a series of regional field guides tied to specific life forms, and (3) a guide to common plants for each SODN unit. These floras range from the small (around 160 species at Casa Grande Ruins National Monument) to massive (around 1,200 species in Saguaro National Park’s Rincon Mountain District). Our methodology builds upon that of inventory efforts completed in the late 1990s and early 2000s. The intention of the project is to conduct a more detailed floristic inventory while building vegetation maps for each park. We first combine the baseline inventory data with all historical studies, then proceed to a comprehensive search of all regional herbarium records. Through this process, we have identified more than 15,000 specimens collected since the creation of the national parks in the region. The herbaria search is followed by broad research in the phylogenetic, systematic, and ecological literature to sort out problematic species and genera. Finally, we scour all agency study records to develop a comprehensive portrait of the floristic research that has been undertaken in each park through the years. The final products of these efforts are not field guides alone, but a cross-platform floristic information system that is being developed for use by land managers, researchers, and the public. Ranging from online databases to printed field guides, to apps for mobile and handheld digital devices, to a range of other digital and print educational tools and resources, the Flora Project hopes to set a standard for floristic research on federal lands in the desert southwest. Plant species checklists for Sonoran Desert Network parks are currently available at http://swbiodiversity.org/seinet/projects/index.php?proj=5 . These versions provide interactive keys that can further help in the identification of plants and provide links to other regional park species checklists. 6 Educational use only; not for sale 2012 NPS National Parks of the Sonoran Desert Network The Sonoran Desert Network is one of 32 National Park Service inventory and monitoring networks nationwide that are implementing vital signs monitoring in order to assess the condition of park ecosystems and develop a stronger scientific basis for stewardship and management of natural resources across the National Park System. The Sonoran Desert Network consists of 10 units in central and southern Arizona and 1 unit in southwestern New Mexico. These units are characteristic of the upper Sonoran subdivision of the Sonoran Desert Ecoregion and the Apache Highlands Ecoregion, and range in size from half a square mile to 517 square miles (147 to 133,882 hectares). Please visit our website for more information and a full list of our active research projects, available publications, and other resources: http://science.nature.nps.gov/im/units/sodn ©circa 1890 C. Mindeleff ©circa Administrative History Of Casa Grande Ruins On June 22, 1892, President Benjamin Harrison created Casa Grande Ruins National Monument by executive order, making it the first cultural or prehistoric site in the United States to receive federal protection. The protected structures comprise a four- story Hohokam structure built during the Classic period of Hohokam habitation, from A.D. 1200 to 1450 (Clemensen 1992), and some 60 documented archeological sites surrounding it. Located on the northern edge of Coolidge, Arizona, southeast of Phoenix, the monument encompasses 191 hectares and is bounded by Arizona Highway 87 to the north and east, by the Pima lateral canal to the south, and agricultural fields to the west. Expansion lands to be acquired by the monument in the future include the prospective Adamsville unit on the opposite side of Highway 87 about 7 kilometers east of the main unit, and several small parcels of currently agricultural land adjacent to or near the main unit. A Brief Environmental History of Casa Grande Ruins National Monument Casa Grande Ruins National Monument is located in south central Arizona, in the Basin and Range physiographic province, where expansion of the earth’s crust resulted in an alternating pattern of widely separated, steep mountain ranges with large alluvial fans or bajadas that gradually slope to the bottoms of broad, flat valleys (Reichhardt 1992). About 1 km north of Casa Grande Ruins is the Gila River, which drains a watershed encompassing much of southern Arizona along with portions of southwestern New Mexico and northern Sonora, Mexico. The monument averages 23 cm of annual precipitation in a bimodal pattern: gentle winter rains from the remnants of Pacific frontal systems, and heavy monsoon rains in summer, caused by convection of moist air from the Gulf of Mexico. Summer high temperatures usually exceed 40°C and winters are mild, rarely below freezing, with diurnal temperature extremes of 20°C or more during much of the year due to the area’s extremely low humidity (Powell et al. 2006). Human history in the Casa Grande area dates back to 5500 B.C., when Archaic peoples hunted and gathered in the area. Subsistence agriculture was not practiced until well after 1000 B.C., with the introduction of maize (corn); beans were introduced around 350 B.C. (Clemensen 1992). Agricultural expansion contributed to a more sedentary population and the beginnings of hydraulic culture. The Hohokam people, who practiced irrigated agriculture, arrived in the middle Gila River Valley about 300 A.D., and flourished there over the next thousand years. As the population grew, canals became larger and more consolidated, eventually reaching 8' deep × 16' wide in some areas; it is believed that the Hohokam were diverting up to half of the river’s volume. Catastrophic flooding of the Gila River, along with several years of low flow, caused the Hohokam to move canal intakes further and further upstream, eventually reaching 18 miles from Casa Grande (Clemensen 1992). The effort to maintain their hydraulic systems, combined with more floods followed by periods of drought, brought on slow social decay that is thought to have contributed to Hohokam abandonment of the area around 1400 A.D. For the next 400 years, habitation of the area was sparse. It was not until after 1853, when the area became part of the United States with the Gadsden Purchase, that Euro-American settlement increased. Prior to widespread Euro- American settlement, there are accounts of massive mesquite and cottonwood bosques along the Gila River in the vicinity of Casa Grande, as well as extensive grasslands (Rea 1997). With the increasing presence of Euro-Americans came the increasing pressures that accompanied livestock grazing. The monument itself was grazed until 1934, when it was finally fenced to protect the structures. With the cessation of the Apache Wars in the late 1800s, many Euro-American settlers descended on the area, rapidly expanding agriculture in the Gila River Valley. Upstream from Casa Grande, at Florence, Arizona, Mormon settlers had begun farming after 1866. The rise of their extensive, direct-diversion irrigation works, followed by groundwater pumping by the 1920s, resulted in expansive development of agricultural land as large volumes of both surface Educational use only; not for sale 9 and groundwater were used (Powell et al. 2006). By 1928, the construction of Coolidge Dam ended the era of the Gila as a free-flowing river through the area. The conversion of the landscape to agriculture continued unabated, and had encircled the monument by 1932. Agriculture in the Coolidge area suffered greatly from overpumping of the water table, which was obvious as the water level of the park’s well dropped from 128 feet below the surface, in the early 1940s, to more than 300 feet below the surface by 1956 (Clemensen 1992, Powell et al.